Leather-sewing machine.



O. E. HOFFMAN.

LEATHER SEWING MACHINE.

APPLICATION FILED 001. 24, 1913.

Patented Dec. 1, 1914 3 SHEETSSHEET l.

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lllll w n W (J w n? a o. E. HOFFMAN.

. LEATHER SE ENG MA HINE.

APPLICATION ED 0012-5, 1913. v L31 19901? Patented Dec. 1, 1914.

W I 3 SHEETS-SHEET 2.

0.3. HOFFMAN. LBATEER SEWING MACHINE. APP LIOATIOH'IILED DOT. 24, 1913.

Patented Dec 1, 1914.

3 BHEETS-SHEET 3 OTTO E. HOFFMAN, F CHICAGQ, ILLINOIS.

LEATHER-SEWING MACHINE.

Specification of Letters Patent.

Patented Dec. 1, 1914.

Application filed October 24, 1913. Serial No. 796,995.

To all whom it may concern:

Be it known that. I, O'r'ro E. HOFFMAN, a

- citizen of the United States, and resident of Chicago, county of Cook, and State of Illinois, have invented certain new and use- 'ful Improvements in Leather-Sewing Machines, of which the following is a specificati0n,'and which are illustrated in the accom panying drawings, forming a part thereof.

' The invention relates to sewing machines, and more particularly to those intended for uniting by seams such heavy materials as leather and the like. I

The object of the invention is to provide a machine of improved construction for sewing such articles as traveling and golf bags, and the invention contemplates a machine adapted for making seams at such parts of these devices as have heretofore been inaccessible for machine sewing.

In the accompanying drawings Figure 1 is a side elevation of a leather sewing machine embodying the improvements provided by the invention, one position of certain parts being indicated by dotteddmes; F ig. 2 is a detail vertical sectional view of the work support and needle operating mechanism; Fig. 3 is a sectional view showing some of the parts illustrated in F 1g. 2 from a different sectional plane; Fig. l is a detail plan view of the machine; Fig. is a detail front elevation of the machine. some parts being shown in section; F ig. (i is a detail front elevation showing a modified form of construction; and Fig. 7 is a detail sectional view taken on the line T-7 of Fig. 3.

The machine illustrated in the drawings is of a form adapted to make a'well known form of chain-stitch seam from a single thread, as A. As the invention contemplates the use of a work support of restricted dimensions, the mechanism shown is also of the. so-callcd awl-feed type wherein the feeding of the work is accomplished by a lateral movement of the awl.

The parts of the machine are conveniently associated upon a frame, which is generally designated by the numeral 10. This frame preferably comprises thefloor plate 11 and pedestal 12 having the overhanging top 13. When the operative parts of the machine are to be driven by power, a drive shaft 14. is preferably located at the top of the pedestal 12. As shown, this drive shaft extends through and is journalcd in brackets, as 15,

at 22 (Figs. 1 and 2) or at 23 which rise from the lop of the pedestal.

.A belt pulley 16 and crank disk 17 are fixed upon opposite ends of the drive shaft 1 1. A sprocket wheel 18 is mounted on the drive shaft 14 intermediate its ends.

One form of work support is generally designated by the numeral 19 in Figs. 1 and 2. A modified form of work support is shown at 20 in Fig. 6. Each of these work supports preferably comprises an upright tubular standard 21, having a pointed tubular anvil block 28 fixed upon its higher end.

Most desirably the tubular standard 21 is horizontally ofi'set intermediate its ends, as

To facilitate the application of the work to the work support, the standard 21 is pivotally secured to the floor plate 11 at a point some distance in front of the foot of the pedestal 12. As shown, a pair of laterally separated pivot lugs 24, 25, rise from the floor plate 11, and the lower end of the standard 21 is bifurcated, its two arms, as 26, 27, being pivotally connected to the pivot lugs 24, 25, respectively, as by bolts 25*.

Any convenient means may be employed for securing the work support, 19 or 20, in

the upright position of service. As shown, a spring bolt 63 (Fig. 6) plays through an.

aperture 64: in one of the pivot lugs, as 25,

for entering an aperture 65 in the corresponding arm, as 27, of the bifurcated lower end of the standard 21 to normally prevent the swinging of the standard away from the said upright position. A pedal 66, pi votally secured to the floor plate at (Wand having a slotted opening 08 for receiving a stud 69 which projects laterally from the bolt 63 adjacent its outer end, serves for withdrawing the bolt. lVhen the bolt is withdrawn the work support, as 19, may be swung forwardly to the position indicated by dotted lines in Fig. 1 for receiving the work.

The usual hooked form of needle is shown at 29. The awl is shown at 30. The needle (Fig. 6). e

29 is carried by the tubular anvil block 28,

for advancing the work, the opening 31 is slotted, as appears in Fig. 3.

The needle 29 is conveniently carried by between the pedestal .19 or 20.

a slide 11, which is mounted within the bore of the tubular anvil block 28and is actuated from the crank disk 17 on the drive shaft 14. As shown, the crank disk 17 carries wrist pin 32, and a pitman 33 operatively connects this wrist pin with a lever 3i which is platell and extends] v its ends, as at 22 (Fig. 2) or 23 (Fig. (3),

. a'second lever 87 extends through the said horizontally offset portion of the-same. "As

" extends through the slide 45.

' 4-0. The 0 shown, this lever is pivotally supported intermediate its ends,

hori'zontally'otfset portion 22 or 23 of the standard. -A link 39,

which is housed within th for connecting one endfof thet'lever 37 with the forward end of the leverjiid. In order that the connection of the-link 39 with the lever 34: may not interfere with tlfi' swinging of the work support, as 19, to the position indicated by dotted lines in Fig. 1, the forward end of the lever is provided with a slot 36 for receiving the connecting pin,as

posite end'of the lever 37 is connected wit 1 the needle slide ll. Usually the connection between the lever 37 and slide 41 will include a link, as'42 or 43, having its opposite ends pivotally attached to the slide 41 and lever 37, respectively.

A cast-01f finger is shown at H. cast-off finger also operates through the opening 31 at the pointed end of the anvil block 28. It moves with the needle 29 during a part of the movement of the latter in each direction. A slide 4.5, which is mounted within the bore of the anvil block 28 alongside of the slide all (Fig. 7) serves for carrying the cast-off finger 44-. A stud d6, fixed in the slide 45 and entering a slotted opening 47 in the slide 41, serves for actuating the cast-off finger 44 to cause it to move in unison with the needle 29 during a part of the movement of the latter in each direction. Preferably a friction element is provided for holding the slide d5 against movement during the initial movement of the slide 41 and needle 29 in each direction. This friction element is shown as taking the form of a disk 48, preferably made of leather, or other yielding material, and fitted within a suitable opening, as 49, in the wall of theanvil block 28 to bear against the A spring finger 50, adjustably held against the outside of the, anvil block 28 by a set-screw- 51 (Fig. 3), bears against awl 30'forfee as upon a pin 38 which e lower upright tubular portion of thestandard 21, serves This l transmitted from 'the head 52 at 83 (Fig. 1).

the outer face of the disk 48 for pressing the same against the slide +5.

A head, generally designated 52, serves for carrying the operative. parts of the machine'which are locatedabove the plane-of '59 (Fig-( 1)., serves for carrying the awl 30 and the usual thread guide or looper 60. This bracket may alsojcarry a spindle fil for receiving a spool, 21562, from which the ng'thework is accomplished by: swinging the bracket 58..

The operating shaft 55 serves for actuatthread A is supplied, '5 The oscillation of the ing the awl 30,presser foot 5.7, and thread guide 60. To this end it is driven at uniform speed with the drive shaft l l, as by means of a sprocket chain which t-urns over the "sprocket. wheel 18 on the drive shaft, an d over'a second sprocket wheel 71 mounted on the operating shaft. The sprocket wheel 71 is preferably located intermediate the ends of theoperating shaft 55. At one end this shaft carries a fly wheel 72. At its otherend it carries a crank 73 for-actuating the awl.

I ,As shown, a crankshaft 74 is mounted upon the head 52, as by being journaled in a bracket lug 75 whichis formed integral therewith. Two cranks 76, 77, are mounted upon the opposite ends of the crank shaft 74: One of these cranks, as 77, is connected with the crank 73 as by a link 78. A. link 7 9 serves for connecting the other'crank, as 76,, with a collar which is fixed upon.the awl 30. As the point of connection between the link 7 9 and crank 7 6 is not -;far removed from the axis of pivotal movement of the frame 58, the swinging of the frame 58 does not interfere with the vertical reciprocation of the awl.

ing shaft-55 adjacent the fly wheel 72, serves for swinging the frame 58 to give the required lateral movement to the awl for feed ing the work. As shown, indvement is the cam 81 to the swinging frame 58 by a' bell crank lever 82. This bell crank lever .is pivotallv supported upon One arm of the bell crank lever carries a stud 84 fo'r'engagement' with the cam 81. The other arm of the bell crank lever is provided with a slot 85 for receivinga stud 86. The stud 86 is adjust'ably fixed in a crank-arm 87, which swings with the frame 58. By shifting the position of the stud .86 upon'the. crankarm '92 for running in the cam groove 89. A

link 93 connects the lower end of the lever 90 with a horizontally movable lever 94. The lever 94 is pivotally secured against the under side of the head 52, as by a screw-bolt Preferably one end, as 96, of the lever 95 is downwardly ,ofiset. This downwardly olisetend 9f the lever is connected with the' thread guide or looper the same, by a link 97.

A cam 98, which is fixed upon the operating shaft adjacent the sprocket wheel 71, serves for raising the presser foot 57. A lever 99 servesior communicating motion from this cam to the presser foot. This lever is pivotally supported intermediate its ends, as between bracket lugs 100 which rise from the upper side of the head 52-. One end of thelcver 99 is upwardly turned, and is equipped with an anti-friction roller 101 for engaging thecam 98. The other end of the lever 99 extends beneath a lug 102,

60, for oscillating which projects laterally from a collar 103 fixed upon the stem of the presser foot 57.

A spring 104, coiled about the stem of the presser foot and reacting between the under side of the head 52 and a second collar 105 which is mounted upon the stem of the presser foot, serves for depressing the presser foot and holding the anti-friction roller 101 in contact with the cam 98.

W hen the work has been fitted over the support 19 or 20, the usual form of chainstitch scam'may be produced by operating the several parts of the machine through the drive shaft 14. The slender form of the worksupport, together with thepointed form of anvil block 28 and horizontal off-set in the work support, permit the stitching to be done at any part of the'work, at the corners ofa suitcase or traveling bag, or at the bottom of a golf bag. The tilting of the work support, as 19, to the position indicatcd by dotted lines in Fig.1, facilitates the application of the work to the work support. If, "for example, the work to be done is that of i'nrming'a seam at the bottom of a goli. bag, the work support, as 19, will be swung forwardly and the body of the bag slipped over the support to bring the pointed an \il block 28 in contact with the bottom of the bag upon the inside. It now the work support, as 19, be returned to the upright position, a scam may be formed at any part of the bottom f the bag.

I claim as my invention 1. In a leather sewing machine, in combination, a. tubular work support having upright end portions and a horizontal inter mediate portion, a needle operating through the higher end of the work support, a head located above the higher end of the work support, stitch-forming elements mounted on the said head and coiiperating with the.

said needle to form a seam, and a. driving mechanism for operating the said stitchforming elements and needle including a lever extending through the bore of the said horizontal intermediate portion of the tubular work support and fulcrumed therein intermediate its ends and plunger-s extending through the bore of the upright end portions of the tubular work support and con nected with the-opposite ends of the said lever and one of said plungers being connected with the needle.

2. In a leather sewing machine, in combination, a downwardly facing work head including a looper, awl and presser foot, an upwardly facing tubular work support mounted for movement. into and out of register with the said work head, a needle operating through the higher end of the work support, and means for driving the said several operative parts including a plunger connected with the needle, said plunger being mounted within the bore of the tubular work support and movable therewith.

3.- In a leather sewing machine, in combination, a tilting tubular post, a needle operating through the higher end of the post, a head fixed in position above the post,

stitch forming elements mdunted upon saidhead and coiiperating with the needle to form a seam when the tilting post is upright, and means for driving the saidseveral operative parts includinga plunger connected with the needle, said plunger being mounted within the bore of the tubular post and movable therewith during-the tilt- I ing of they post.

4. In a leather sewing machine, in combination, a tilting tubular post, a needle opcrating through the higher end of the post, a head fixed in position above the post, stitch forming elements mounted upon said ,head and coiiperating with the needle to form a seam when the, tilting post is upright, means for driving the said several operative parts including a plunger connected with the needle, said plunger being mounted wi thin the bore of the tubular post and movable therewith during the tilting of the post, and a latch for securing the post in upright position.

5. In a leather sewing machine, in combination, an upright tubular work support which is laterally otl'set intermediate its ends, the two end portions of said support being parallel, a needle operating through the higher end of the work support, a head located above the higher end of the work support, stitch forming elements mounted on the said head and cooperating with (he said needle to form a seam, a drive sl ait, mechanism connecting the drive shaft and the said stitch forming elements and mechanism connecting the drive shaftand the said needle, the last named mechanism being operable through the bore of the two parallel end portions and of the laterally olls'et intermediate portion of the tubular work sup port.

G. In a leather sewing machine, in coinhination, a normally upright tilting tnlndar work support which is laterally oll'set intermediate its ends, the two end portions of said support being parallel, a needle operating through the higher end of the worlrsnpport, a head located above the higher end of the work support, stitch forming, elements mounted on the head and cooperating with the said needle to form a seam, a drive shaft,

mechanism connecting the drive shaft and the said stitch forming elements and inechanism connecting the drive shaft and the said medic, the last named mechanism being operahle through the bore of the two parallel end portions and 01 the laterally offset int rmediate portion of. the tubular Work support.

To In a leather sewing machine, in combination, a head, a tilting work supporting post, the tilting of the post serving to permit movement oi the post between positions in which the higher end of the post registers wit the head and spaced apart from the head for rereivir'lg the work, respectively, and a plurality of stitch "Forming lements, a part of said elements being carried by the head, a pa rt of said elements being carried l the tiltingwork SllPf-JOlilllg post and all of said elements cooperating to form a seam when the higher end of the post registers with the headl OTTO E. HOFFMAN. \Vitnesses CHARLES .B. GILLSON, E. M. KLA'rcinaR. 

